Metal matrix composites (MMC's) are metal or alloys strengthen with tiny inclusions of another material which inhibit crack growth and increase performance. MMC's have mechanical properties that are superior to those of most pure metals, some alloys and most polymer-matrix composites, especially in high temperatures. The ability to tailor both mechanical and physical characteristic of MMC's is a unique and important feature of these materials.
Although the technology is relatively young, there are a number of sufficient applications most notably, the space shuttle fuselage struts, space telescope boom-waveguides, and diesel engines pistons. In the future, metal matrix composites are expected to become an important class of materials in numerous other commercial applications.
Although many other metal-matrix composites having widely different properties exist, some general advantages of these materials over competing materials can be cited. MMC's are known to have higher strength-to-density ratios and higher stiffness-to-density ratios with better fatigue resistances than most unreinforced metals and some polymer matrix composites.
Light weight metal composites having high tensile modulus, good ductility, toughness, formability and machine ability and methods for making the same are disclosed in my earlier U.S. Pat. No. 5,511,603. As disclosed therein, such composites include a uniform distribution of ceramic particles having an average particle size of no greater than about one micron. The metal-matrix composites disclosed therein exhibit high strength at room and elevated temperatures since the small reinforcement size and inner particle spacing meets the criteria for dispersion strengthening. The small uniformly distributed ceramic particles permit the composites to behave much more like a metal than a typical metal matrix composite, permitting their use in applications requiring greater ductility, toughness and formability. These composites also provide unexpectedly excellent machineability and ductility, even at relatively high ceramic loadings.
It is now believed that there may be a significant commercial demand for a reinforced metal matrix composite for thermal management for automotive and other applications, for example, disc brake rotors and brake drums. For such applications, the materials need high wear resistance and high thermal conductivity. It is also desirable that such materials are readily castable using available technology at a competitive cost. Accordingly, there is a need for economically producing metal-ceramic composites without expensive heavy press machinery and complicated processing techniques.